To ensure that the virtual machine objects continue to run smoothly during a rack failure, you can group hosts in different fault domains.

When you provision a virtual machine on the cluster with fault domains, vSAN distributes protection components, such as witnesses and replicas of the virtual machine objects across different fault domains. As a result, the vSAN environment becomes capable of tolerating entire rack failures in addition to a single host, storage disk, or network failure.


  • Choose a unique fault domain name. vSAN does not support duplicate fault domain names in a cluster.

  • Verify the version of your ESXi hosts. You can only include hosts that are 6.0 or later in fault domains.

  • Verify that your vSAN hosts are online. You cannot assign hosts to a fault domain that is offline or unavailable due to hardware configuration issue.


  1. Navigate to the vSAN cluster.
  2. Click the Configure tab.
  3. Under vSAN, click Fault Domains.
  4. Click the Create a new fault domain icon ().
  5. Enter the fault domain name.
  6. From the Show drop-down menu, select Hosts not in fault domain to view the list of hosts that are not assigned to a fault domain or select All Hosts to view all hosts in the cluster.
  7. Select one or more hosts to add to the fault domain.

    A fault domain cannot be empty. You must select at least one host to include in the fault domain.

  8. Click OK.

    The selected hosts appear in the fault domain.